Field of the Invention
The present invention relates to an image forming apparatus, a control method therefor, and a computer-readable storage medium storing a program for implementing the control method.
Description of the Related Art
As an image forming apparatus becomes increasingly sophisticated, the time for the image forming apparatus to become operable after a user turns on a power switch tends to increase. On the other hand, there is a speed-up startup technique using a suspend method in which electric current is kept passed through a main memory when a user turns off a power switch.
In this suspend method, a state when a power switch is turned off is stored, and at next startup, the apparatus is returned to the stored state, but at this time, a control program is not reset, and hence memory may become increasingly fragmented.
As a technique to solve this problem, there is a hibernation startup technique according to which a memory image at the start of operation is stored in a storage device as a snap shot called as a hibernation image, and at startup, the snapshot is transferred to memory, enabling high-speed startup. According to this hibernation startup technique, however, operation cannot be started unless a hibernation image has been created.
For this reason, there are many cases where such apparatuses as image processing apparatuses in which a variety of hardware and software options can be added and deleted, and initialization sequences, initial screens, and so on are changed cannot be started using a hibernation image. Thus, the hibernation startup technique is not suitable for image processing apparatuses.
To solve this problem, there has been disclosed a technique that creates a hibernation image again when changing hardware and software configurations (see, for example, Japanese Laid-Open Patent Publication (Kokai) No. 2012-18554). Specifically, according to this technique, a hibernation image is divided into a common part and an optional part, and all the images are stored in a storage device in advance. By optional settings, combinations of images in the optional part are determined at previous termination or at startup to create the entire hibernation image.
To solve the above problem, there has also been disclosed a technique that deletes a hibernation image when changing software configurations (see, for example, Japanese Laid-Open Patent Publication (Kokai) No. 2013-004044). Specifically, according to this technique, when such a change in software that it can be determined that a stored hibernation image is unusable, the stored hibernation image is deleted, and at next startup, no hibernation image is used.
According to the technique disclosed in Japanese Laid-Open Patent Publication (Kokai) No. 2012-18554, it is possible to cope with configuration changes by detecting changes in the configurations of hardware and software and combining hibernation images stored in advance to create the entire hibernation image.
According to this technique disclosed in Japanese Laid-Open Patent Publication (Kokai) No. 2013-004044, a hibernation image is deleted when the configuration of software is changed, and cold booting (normal startup) is forced to be performed at next startup, so that mismatch between user settings and a hibernation image can be avoided.
According to the technique disclosed in Japanese Laid-Open Patent Publication (Kokai) No. 2012-18554, however, imagining all patterns and storing partial hibernation images in advance is not efficient because many optional functions can be added or deleted in an image processing apparatus. Moreover, according to this method, managing many versions and keeping consistency of versions are difficult. Further, according to the technique disclosed in Japanese Laid-Open Patent Publication (Kokai) No. 2013-004044, it is impossible to cope with changes in device configuration.
Thus, the hibernation function according to the prior arts has the problem of not being able to support device connection states which are different at power-off and at next startup.